Silicon carbide heating elements have been used for many years for various industrial heating applications. In such applications where it is desired that the heating element be below the surface of a molten metal, for example such as in a molten aluminum casting furnace resevoir, it is desirable to enclose the heating element in an outer tube from which the heating element is electrically insulated. When single heating elements are utilized in a tube it is difficult to get the amount of power generated from each heating element which is desired for an efficient and economical construction.
In the present invention the heating element is formed of a plurality of silicon carbide rods, four being the minimum needed for making an immersion type heater. Each silicon carbide rod has a hot end and a cold end. The heating element is also supplied with an input electrical terminal and an output electrical terminal. At least two rods are connected to each output terminal at their cold ends. The hot ends of all of the rods are connected together by a silicon carbide bridge element. As a result of this arrangement each electrical heating circuit includes at least two input rods in parallel and two output rods in parallel, with the input rods in series with the output rods. With this arrangement the input and output electrical terminals are positioned adjacent each other and the heating element is in the form of a U-shape to provide a concentrated heat source which can be inserted inside a closed end silicon carbide tube to make an efficient emmersion heater having a high unit KW output.